Highly Efficient Allyl Cross-Coupling Reactions of Allylindiums with

Oct 12, 2002 - Sanghyuck Kim , Cheol-Eui Kim , Boram Seo , and Phil Ho Lee. Organic Letters 2014 ... The Journal of Organic Chemistry 2011 76 (3), 760...
9 downloads 3 Views 83KB Size
Download PDF
Highly Efficient Allyl Cross-Coupling Reactions of Allylindiums with Organic Electrophiles

SCHEME 1

Kooyeon Lee, Jinsung Lee, and Phil Ho Lee* Department of Chemistry, Kangwon National University, Chunchon 200-701, Kangwondo, Republic of Korea [email protected] Received June 29, 2002

Abstract: This paper describes highly efficient allyl crosscoupling reactions of allylindiums with organic electrophiles such as aryl and vinyl triflates, vinyl halides, dibromoolefin, and alkynyl iodide. The reactions were carried out using 4 mol % Pd(PPh3)4 in the presence of 3 equiv of LiCl in DMF at 100 °C under a nitrogen atmosphere. Allylindium, generated from the reaction of 1 equiv of indium with 1.5 equiv of allyl halide, gave the best result as a coupling partner. The present method is mild and simple to apply, and it produces a diverse range of allylic compounds in good to excellent yields.

Coupling reactions of organometallic compounds with organic electrophiles catalyzed by transition metals have received much attention in the area of synthetic methods for C-C bond formation.1 Especially, allyl cross-coupling reactions have been focused on in recent years because the double bond can be further functionalized.2 One of the most frequently used methods for allyl cross-coupling reactions is the use of allylstannane for coupling partners, which has attracted much attention as a result of its availability as well as its air- and moisture-stability, and its compatibility with a variety of functional groups. Using allylstannanes for nucleophilic coupling partners, however, is faced with several limitations: (1) difficulties associated with the preparation of regiochemically defined allylstannanes, (2) its tendency to undergo allylic isomerization, (3) tin removal from the product, and (4) tin toxicity.2b,3 On the other hand, the Pd-catalyzed (1) (a) Heck, R. F. Palladium Reagents in Organic Synthesis; Academic Press: New York, 1985. (b) Trost, B. M.; Verhoeven, T. R. In Comprehensive Organometallic Chemistry; Wilkinson, G., Stone, F. G., Abel, E. W., Eds.; Pergamon: Oxford, UK, 1982; Vol. 8, pp 799938. (c) Farina, V. In Comprehensive Organometallic Chemistry II; Wilkinson, G., Stone, F. G., Abel, E. W., Eds.; Pergamon: Oxford, UK, 1995; Vol. 12, pp 161-240. (d) Tsuji, J. Palladium Reagents and Catalyst; Wiley: Chichester, UK, 1995; Chapter 4. (e) Diederich, F.; Stang, P. J., Eds. Metal-Catalyzed Cross-couplings Reactions; WileyVCH: Weinheim, Germany, 1998. (f) Malleron, J.; Fiaud, J.; Legros, J. Handbook of Palladium-Catalyzed Organic Reactions; Academic Press: San Diego, CA, 1997. (2) (a) Labadie, J. W.; Tueting, D.; Stille, J. K. J. Org. Chem. 1983, 48, 4634. (b) Stille, J. K. Angew. Chem., Int. Ed. Engl. 1986, 25, 508. (c) Echavarren, A. M.; Stille, J. K. J. Am. Chem. Soc. 1987, 109, 5478. (d) Verhac, J.-B.; Pereyre, M.; Quintard, J.-P. Tetrahedron 1990, 46, 6399. (e) Yamamoto, Y.; Hatsuya, S.; Yamada, J.-i. J. Org. Chem. 1990, 55, 3118. (f) Farina, V.; Krishnan, B. J. Am. Chem. Soc. 1991, 113, 9585. (3) (a) Farina, V.; Krishnamurthy, V.; Scott, W. J. The Stille Reaction; Wiley: New York, 1998. (b) Pereyre, M.; Quintard, J.; Rahm, A. Tin in Organic Synthesis; Butterworth: London 1987. (c) Stille, J. K. Pure Appl. Chem. 1985, 57, 1771. (d) Mitchell, T. N. Synthesis 1992, 803. (e) Farina, V.; Krishnamurthy, V.; Scott. W. J. Org. React. 1997, 50, 1.

reaction of allylmetals containing Mg, Zn, or Al with aryl and alkenyl halides has not given the desired crosscoupling products in high yields. Inhibition of Pd catalysis by the allylmetal reagents may be suspected, since the charge-affinity-inverted reaction of aryl and alkenylmetals with ally electrophiles is highly satisfactory.1e Therefore, overcoming these difficulties is a prerequisite for developing new allylmetals as coupling partners. In connection with our current research interest in the synthetic utility of organoindium,4 we had previously reported on Pd-catalyzed cross-coupling reactions of allylindiums with aryl halides.5,6 Here we examine the feasibility and efficiency of Pd-catalyzed allyl crosscoupling reactions of in situ generated allylindiums with a variety of organic electrophiles such as aryl and vinyl triflates, vinyl halides, dibromoolefin, and alkynyl iodide (Scheme 1). Of the catalytic systems screened, the best results were obtained with 4 mol % Pd(PPh3)4 in the presence of 3 equiv of LiCl in DMF at 100 °C under a nitrogen atmosphere. Allylindium, in situ generated from the reaction of 1 equiv of indium with 1.5 equiv of allyl halide, gave the best result as a coupling partner. To demonstrate the efficiency and scope of the present method, we applied this catalytic system to a variety of allyl halides and organic electrophiles such as aryl and vinyl triflates, vinyl halide, dibromoolefin, and alkynyl iodide. The presence of various alkyl substituents at the R and γ position did not diminish the efficiency and selectivity for the allyl halides as coupling partners. The results are summarized in Table 1. Under the optimized conditions, (4) (a) Lee, P. H.; Bang, K.; Lee, K.; Lee, C.-H.; Chang, S. Tetrahedron Lett. 2000, 41, 7521. (b) Lee, P. H.; Ahn, H.; Lee, K.; Sung, S.-Y.; Kim, S. Tetrahedron Lett. 2001, 42, 37. (c) Lee, P. H.; Lee, K.; Kim, S. Org. Lett. 2001, 3, 3205. (d) Lee, P. H.; Bang, K.; Ahn, H.; Lee, K. Bull. Korean Chem. Soc. 2001, 22, 1385. (e) Lee, P. H.; Seomoon, S.; Lee, K. Bull. Korean Chem. Soc. 2001, 22, 1380. (f) Lee, P. H.; Lee, K.; Sung, S.-Y.; Chang, S. J. Org. Chem. 2001, 66, 8646. (g) Lee, P. H.; Lee, K.; Chang, S. Synth. Commun. 2001, 31, 3189. (h) Lee, P. H.; Bang, K.; Lee, K.; Sung, S.-Y.; Chang, S. Synth. Commun. 2001, 31, 3781. (i) Lee, P. H.; Sung, S.-Y.; Lee, K.; Chang, S. Synlett 2002, 146. (5) Lee, P. H.; Sung, S.-Y.; Lee, K. Org. Lett. 2001, 3, 3201. (6) For some previously reported examples of indium-mediated crosscoupling reactions, see: (a) Nomura, R.; Miyazaki, S.-I.; Matsuda, H. J. Am. Chem. Soc. 1992, 114, 2738. (b) Perez, I.; Sestelo, J. P.; Sarandeses, L. A. Org. Lett. 1999, 1, 1267. (c) Gelman, D.; Schumann, H.; Blum, J. Tetrahedron Lett. 2000, 41, 7555. (d) Perez, I.; Sestelo, J. P.; Sarandeses, L. A. J. Am. Chem. Soc. 2001, 123, 4155. (e) Hirashita, T.; Yamamura, H.; Kawai, M.; Araki, S. Chem. Commun. 2001, 387. (f) Takami, K.; Yorimitsu, H.; Shnokubo, H.; Matsubara, S.; Oshima, K. Org. Lett. 2001, 3, 1997. (g) Lee, P. H.; Sung, S.-Y.; Lee, K. Org. Lett. 2001, 3, 3201.

10.1021/jo026121u CCC: $22.00 © 2002 American Chemical Society

Published on Web 10/12/2002

J. Org. Chem. 2002, 67, 8265-8268

8265

TABLE 1. Pd-Catalyzed Allyl Cross-Coupling Reactions of Allylindiums with Organic Electrophiles

a 2 mol % Pd dba CHCl /16 mol % PPh was used as catalyst. b Isomeric ratio of 25 and 26. c Isomeric ratio of crotyl bromide: cis:trans 2 3 3 3 ) 1:5. d Isomeric ratio of 27: cis:trans ) 1:1. e 27(R):28(γ) ratio. f Cis:trans ratio. g Isomeric ratio of β-bromostyrene: cis:trans ) 1:4. h 2 equiv of In and 3 equiv of allyl iodide were used. i Pd(0) catalyst was not used. Yield of 1-allyl-3-iodo-2-cyclohexenol.

8266 J. Org. Chem., Vol. 67, No. 23, 2002

6 was treated with allyl iodide and indium to produce 16 in 92% yield (entry 1). Whereas addition of prenylindium to carbonyl groups usually yielded the product resulting from γ-attack,7 we found that the reaction of 6 with prenylindium regioselectively produced 17 resulting from R-attack due to the steric effect in 87% yield (entry 2). The reaction of 7 with 3-bromocyclohexene in the presence of indium afforded 2-(2′-cyclohexenyl)naphthalene in 87% yield (entry 6). Vinyl triflates worked equally well with allylindiums (entries 7-9), producing allylic compounds in good to excellent yield. R-Bromostyrene was treated with allylindium to give 2-phenyl-1,4-pentadiene and trans-1-phenyl-1,4-pentadiene in 65% and 32% yields, respectively. Although mechanism of formation of trans-1-phenyl-1,4-pentadiene is not clear at the present time, we believe that 1,4-diene 26 was produced via oxidative addition of Pd(0) to R-bromostyrene, dehydropalladation due to steric effect to produce phenylacetylene, hydropalladation to phenylacetylene, followed by the allyl cross-coupling reaction (entry 10).8 The reaction of R-bromostyrene with crotyl bromide (cis:trans ) 1:5) in the presence of indium produced a 1.9:1 mixture of R (cis:trans ) 1:1, 27) and γ products (28), but the product resulting from R attack predominated (entry 11). Treatment of 10 with geranylindium produced the desired product 30 in 97% yield (entry 13). The reaction of β-bromostyrene (cis:trans ) 1:4) with allylindium gave cross-coupling product 1-phenyl-1,4-pentadiene (cis:trans ) 1:4, 31) in 96% yield (entry 14). In the case of β,β-dibromostyrene (12),9 double cross-coupling product 32 was obtained in 92% yield with 2 equiv of allylindium (entry 15). It should be noted that 2-iodo or 3-iodo-2cyclohexen-1-one having a labile ketone group toward allylindium provided the desired products 33 and 34 in good yields (entries 16 and 17), respectively. The reaction of 14 with allylindium in the absence of Pd(0) produced 1-allyl-3-iodo-2-cyclohexenol in 77% yield. These results mean that 3-allyl-2-cyclohexen-1-one was produced not via 1,4-addition of allylindium followed by an elimination reaction, but through a Pd-catalyzed cross-coupling reaction. Treatment of iodophenylacetylene10 with prenylindium regioselectively produced 5-methyl-1-phenyl-4hexen-1-yne in 82% yield (entry 19). In conclusion, we have shown here several noteworthy features (availability, ease of preparation and handling, high reactivity as well as selectivity, and operational simplicity) of allylindium reagents for the cross-coupling reaction. The present method is mild and simple to apply, and it produces a diverse range of allylic compounds in good to excellent yields. This protocol can be readily applied to cross-coupling reactions with aryl and vinyl triflates, vinyl halides, dibromoolefin, and alkynyl iodide. (7) (a) Araki, S.; Ito, H.; Butsugan, Y. J. Org. Chem. 1988, 53, 1833. (b) Araki, S.; Katsumura, N.; Ito, H.; Butsugan, Y. Tetrahedron Lett. 1989, 30, 1581. (c) Isaac, M. B.; Chan, T.-H. Tetrahedron Lett. 1995, 36, 8957. (d) Loh, T.-P.; Li, X.-R. Angew. Chem., Int. Ed. Engl. 1997, 36, 980. (8) Although we tried to detect phenylacetylene to confirm the proposed mechanism, we failed to detect phenylacetylene. Efforts to further understand the mechanism are currently in progress. (9) (a) Corey, E. J.; Fuchs, P. L. Tetrahedron Lett. 1972, 13, 3769. (b) Ramirez, F.; Desai, N. B.; McKelvie, N. J. Am. Chem. Soc. 1962, 84, 1745. (c) Shen, W.; Wang, L. J. Org. Chem. 1999, 64, 8873. (10) (a) Rao, M. L. N.; Periasamy, M. Synth. Commun. 1995, 25, 2295. (b) Jeffery, T. Chem. Commun. 1988, 909.

Experimental Section Typical Experimental Procedure. To a suspension of Pd(PPh3)4 (23.0 mg, 4 mol %) and lithium chloride (63.5 mg, 1.5 mmol) in DMF (1 mL) was added trifluoromethanesulfonic acid naphthalen-1-yl ester (138.1 mg, 0.5 mmol) at room temperature under a nitrogen atmosphere. After 15 min, allyl indium, which is generated from allyl iodide (126.0 mg, 0.75 mmol) and indium (57.0 mg, 0.5 mmol) in DMF (1 mL), was added and the mixture was stirred at 100 °C for 1 h. The reaction mixture was quenched with NaHCO3 (saturated aqueous). The aqueous layer was extracted with ether (3 × 20 mL), and the combined organics were washed with water and brine, dried with MgSO4, filtered, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using n-hexane to give 1-allylnaphthalene (77.3 mg, 92%). 1H NMR (400 MHz, CDCl3) δ 8.01 (d, J ) 8.08 Hz, 1H), 7.83 (t, J ) 7.76 Hz, 1H), 7.72 (d, J ) 6.89 Hz, 1H), 7.50-7.42 (m, 2H), 7.39 (d, J ) 7.25 Hz, 1H), 7.32 (d, J ) 6.89 Hz, 1H), 6.16-6.65 (m, 1H), 5.115.06 (m, 2H), 3.82 (d, J ) 6.30 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 135.13, 133.27, 132.01, 130.15, 126.84, 125.13, 124.44, 123.96, 123.77, 123.68, 122.19, 114.33, 35.43; IR (film) 3003, 2916, 1684, 1606, 1414, 1358 cm-1; HRMS (EI) calcd for C13H12 M+ 168.0939, found 168.0934. 1-Prenylnaphthalene (17): 1H NMR (400 MHz, CDCl3) δ 8.03 (d, J ) 8.04 Hz, 1H), 7.85 (d, J ) 9.05 Hz, 1H), 7.71 (d, J ) 8.11 Hz, 1H), 7.49 (m, 2H), 7.40 (dd, J ) 7.91, 7.25 Hz, 1H), 7.33 (d, J ) 6.83 Hz, 1H), 5.40 (t, J ) 6.92 Hz, 1H), 3.77 (d, J ) 6.92 Hz, 2H), 1.80 (s, 3H), 1.76 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 137.78, 133.85, 132.69, 132.04, 128.30, 126.56, 125.71, 125.64, 125.58, 125.44, 124.00, 122.88, 31.78, 25.74, 17.95; IR (film) 3053, 2986, 2305, 1422, 1269 cm-1; HRMS (EI) calcd for C15H16 M+ 196.1252, found 196.1251. 1-(2′-Cyclohexenyl)naphthalene (18): 1H NMR (400 MHz, CDCl3) δ 8.14 (d, J ) 8.27 Hz, 1H), 7.87 (d, J ) 8.07 Hz, 1H), 7.72 (d, J ) 7.76 Hz, 1H), 7.53-7.38 (m, 4H), 6.04-5.99 (m, 1H), 5.83 (dd, J ) 9.98, 1.80 Hz, 1H), 4.24-4.22 (m, 3H), 2.21-2.11 (m, 3H), 1.76-1.66 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 137.78, 133.85, 132.69, 132.04, 128.30, 126.56, 125.71, 125.64, 125.58, 125.44, 124.00, 122.88, 31.78, 25.74, 17.95; IR (film) 3053, 2978, 2870, 2305, 1422 cm-1; HRMS (EI) calcd for C16H16 M+ 208.1252, found 208.1256. 2-Allylnaphthalene (19): 1H NMR (400 MHz, CDCl3) δ 7.86-7.77 (m, 3H), 7.63 (s, 1H), 7.49-7.40 (m, 3H), 7.33 (dd, J ) 8.46, 1.42 Hz, 1H), 6.05 (ddt, J ) 16.98, 10.09, 6.77 Hz, 1H), 5.16-5.11 (m, 2H), 3.55 (d, J ) 6.66 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 137.55, 137.32, 133.65, 132.12, 128.04, 127.62, 127.48, 127.39, 126.66, 125.93, 125.27, 40.36; IR (film) 3003, 2916, 1684, 1606, 1414, 1358 cm-1; HRMS (EI) calcd for C13H12 M+ 168.0939, found 168.0934. 2-Prenylnaphthalene (20): 1H NMR (400 MHz, CDCl3) δ 7.84-7.78 (m, 3H), 7.64 (s, 1H), 7.49-7.35 (m, 2H), 7.36 (d, J ) 8.33 Hz, 1H), 5.45 (t, J ) 10.24 Hz, 1H), 3.54 (d, J ) 7.31 Hz, 2H), 1.82 (s, 3H), 1.80 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 139.76, 134.13, 133.26, 128.29, 128.01, 127.86, 127.80, 126.51, 126.26, 125.47, 123.46, 34.97, 26.22, 18.33; IR (film) 3691, 3054, 2986, 2305, 1422, 1270 cm-1; HRMS (EI) calcd for C15H16 M+ 196.1252, found 196.1258. 2-(2′-Cyclohexenyl)naphthalene (21): 1H NMR (400 MHz, CDCl3) δ 7.81-7.77 (m, 3H), 7.64 (s, 1H), 7.46-7.36 (m, 3H), 5.97-5.94 (m, 1H), 5.81 (dd, J ) 10.04, 1.42 Hz, 1H), 3.56 (s, 1H), 2.12-2.05 (m, 3H), 1.81-1.70 (m, 1H), 1.67-1.61 (m, 2H); 13C NMR (100 MHz, CDCl ) δ 144.05, 133.54, 132.15, 130.05, 3 128.64, 127.84, 127.58, 127.55, 126.71, 125.81, 125.79, 125.14, 41.90, 32.41, 25.09, 21.12; IR (film) 3053, 2978, 2870, 2305, 1422 cm-1; HRMS (EI) calcd for C16H16 M+ 208.1252, found 208.1256. 1-Allyl-4-(tert-butyl)-1-cyclohexene (22): 1H NMR (400 MHz, CDCl3) δ 5.80 (ddt, J ) 16.1, 9.96, 6.89 Hz, 1H), 5.43 (d, J ) 3.61 Hz, 1H), 5.02 (d, J ) 15.33 Hz, 1H), 4.99 (d, J ) 8.31 Hz, 1H), 2.68 (d, J ) 6.66 Hz, 2H), 2.05-1.74 (m, 5H), 1.261.12 (m, 2H), 0.86 (s, 9H); 13C NMR (100 MHz, CDCl3) δ 136.99, 136.14, 122.08, 115.41, 44.15, 42.01, 32.20, 29.83, 27.25, 26.87, 24.26; IR (film) 3054, 2862, 2305, 1637, 1423, 1267 cm-1; HRMS (EI) calcd for C13H22 M+ 178.1721, found 178.1717.

J. Org. Chem, Vol. 67, No. 23, 2002 8267

4-Allyl-8-methoxy-1,2-dihydronaphthalene (23): 1H NMR (400 MHz, CDCl3) δ 7.15 (d, J ) 7.86 Hz, 1H), 6.92 (d, J ) 7.86 Hz, 1H), 6.79 (d, J ) 8.20 Hz, 1H), 5.95 (ddt, J ) 16.70, 10.17, 6.35 Hz, 1H), 5.90-5.88 (m, 1H), 5.11 (dd, J ) 17.16, 1.58 Hz, 1H), 5.06 (dd, J ) 10.07, 1.58 Hz, 1H), 3.83 (s, 3H), 3.18 (dd, J ) 6.36, 1.28 Hz, 2H), 2.76 (t, J ) 8.07 Hz, 2H), 2.27-2.21 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 156.02, 136.79, 135.91, 134.47, 126.17, 124.40, 115.96, 115.89, 109.46, 55.48, 37.37, 22.53, 19.89; IR (film) 3054, 2986, 1573, 1422, 1263 cm-1; HRMS (EI) calcd for C14H16O M+ 200.1201, found 200.1202. 4-(2′-Cyclohexenyl)-8-methoxy-1,2-dihydronaphthalene (24): 1H NMR (400 MHz, CDCl3) δ 7.18 (t, J ) 8.03 Hz, 1H), 7.00 (d, J ) 9.82 Hz, 1H), 6.78 (d, J ) 8.19 Hz, 1H), 5.895.82 (m, 2H), 5.68-5.64 (m, 1H), 3.83 (s, 3H), 3.43 (s, 1H), 2.832.62 (m, 2H), 2.25-2.19 (m, 2H), 2.04-1.86 (m, 3H), 1.70-1.53 (m, 3H); 13C NMR (100 MHz, CDCl3) δ 156.59, 139.78, 136.19, 130.48, 128.45, 126.61, 126.22, 125.44, 115.94, 109.66, 55.96, 37.05, 31.78, 29.10, 25.74, 22.94, 20.64, 20.40; IR (film) 3054, 2986, 2305, 1422, 1265 cm-1; HRMS (EI) calcd for C17H20O M+ 240.1514, found 240.1510. 2-Phenyl-1,4-pentadiene (25): 1H NMR (400 MHz, CDCl3) δ 7.44 (d, J ) 7.15 Hz, 2H), 7.36-7.42 (m, 3H), 5.94-5.86 (m, 1H), 5.39 (s, 1H), 5.12 (d, J ) 13.69 Hz, 1H), 5.10 (s, 1H), 5.07 (d, J ) 8.60 Hz, 1H), 3.25 (d, J ) 6.49 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 146.33, 140.94, 136.20, 128.25, 127.44, 125.99, 116.46, 113.15, 39.51; IR (film) 3053, 2986, 2305, 1422, 1265 cm-1; HRMS (EI) calcd for C11H12 M+ 144.0939, found 144.0935. trans-1-Phenyl-1,4-pentadiene (26): 1H NMR (400 MHz, CDCl3) δ 7.36-7.19 (m, 5H), 6.41 (d, J ) 15.90 Hz, 1H), 6.23 (dt, J ) 15.77, 6.66 Hz, 1H), 5.96-5.86 (m, 1H), 5.11 (d, J ) 17.13 Hz, 1H), 5.07 (d, J ) 10.12 Hz, 1H), 2.96 (t, J ) 7.04 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 137.62, 136.47, 130.85, 128.49, 128.18, 127.02, 126.04, 115.67, 37.00; IR (film) 3053, 2986, 2395, 1421, 1270 cm-1; HRMS (EI) calcd for C11H12 M+ 144.0939, found 144.0935. 2-Phenyl-1,4-hexadiene (27): 1H NMR (400 MHz, CDCl3) cis/trans mixture δ 7.44-7.24 (m, 5H), 5.60-5.46 (m, 4H), 5.36 (s, 1H), 5.34 (s, 1H), 5.10 (s, 1H), 5.08 (s, 1H), 3.21 (d, J ) 6.99 Hz, 2H), 3.17 (s, 2H), 1.67 (s, 3H), 1.65 (s, 3H); 13C NMR (100 MHz, CDCl3) cis isomer δ 147.16, 141.30, 128.13, 127.39, 126.98, 126.00, 125.45, 112.43, 32.77, 12.81, trans isomer δ 146.80, 114.17, 128.22, 127.92, 127.35, 126.66, 125.99, 112.62, 41.85, 19.25; IR (film) 3053, 2986, 2305, 1422, 1269 cm-1; HRMS (EI) calcd for C12H14 M+ 158.1096, found 158.1091 (cis isomer), 158.1091 (trans isomer). 3-Methyl-2-phenyl-1,4-pentadiene (28): 1H NMR (400 MHz, CDCl3) δ 7.44-7.24 (m, 5H), 5.91 (ddd, J ) 17.06, 10.39, 6.67 Hz, 1H), 5.26 (s, 1H), 5.08 (s, 1H), 5.07 (d, J ) 15.06 Hz, 1H), 5.01 (d, J ) 10.59 Hz, 1H), 3.40 (quint, J ) 6.85 Hz, 1H), 1.21 (d, J ) 6.98 Hz, 3H); 13C NMR (100 MHz, CDCl3) δ 152.65, 142.38, 142.20, 128.62, 128.15, 127.20, 113.67, 112.14, 38.31, 17.95; IR (film) 3053, 2986, 2305, 1422, 1269 cm-1; HRMS (EI) calcd for C12H14 M+ 158.1096, found 158.1094. r-(2′-Cyclohexenyl)styrene (29): 1H NMR (400 MHz, CDCl3) δ 7.40-7.23 (m, 5H), 5.86-5.82 (m, 1H), 5.73-5.70 (m, 1H), 5.29 (s, 1H), 5.05 (s, 1H), 2.04-1.99 (m, 2H), 1.83-1.48 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 152.44, 141.99, 128.24, 128.18, 128.01, 127.16, 126.56, 113.06, 39.87, 28.39, 25.24, 20.29; IR (film) 3053, 2986, 1531, 1351, 1267 cm-1; HRMS (EI) calcd for C14H16 M+ 184.1252, found 184.1251. 5,9-Dimethyl-2-phenyl-1,4,8-decatriene (30): 1H NMR (400 MHz, CDCl3) cis isomer δ 7.45-7.24 (m, 5H), 5.32 (s, 1H), 5.265.22 (m, 1H), 5.13-5.11 (m, 1H), 5.07 (t, J ) 1.39 Hz, 1H), 2.092.10 (m, 4H), 1.72 (s, 3H), 1.69 (s, 3H), 1.66 (s, 3H), trans isomer δ 7.45-7.24 (m, 5H), 5.32 (s, 1H), 5.26-5.22 (m, 1H), 5.09-5.05 (m, 1H), 5.07 (t, J ) 1.39 Hz, 1H), 3.18 (d, J ) 6.86 Hz, 2H), 1.72 (s, 3H), 1.69 (s, 3H), 5.40 (t, J ) 6.92 Hz, 1H), 3.77 (d, J ) 6.92 Hz, 2H), 2.09-2.01 (m, 4H), 1.65 (s, 3H), 1.61 (s, 3H), 1.59 (s, 3H); 13C NMR (100 MHz, CDCl3) cis isomer δ 147.46, 141.47, 136.88, 131.67, 128.20, 127.50, 126.01, 124.20, 122.47, 112.28, 33.59, 32.02, 26.50, 25.73, 17.66, 16.03, trans isomer δ 147.19,

8268 J. Org. Chem., Vol. 67, No. 23, 2002

141.54, 136.80, 131.42, 128.18, 127.29, 126.23, 124.25, 121.89, 112.12, 39.71, 33.78, 26.59, 25.70, 23.43, 17.69; IR (film) 3054, 2986, 2305, 1674, 1422, 1269 cm-1; HRMS (EI) calcd for C18H24 M+ 240.1878, found 240.1877 (cis isomer), 240.1877 (trans isomer). 1-Phenyl-1,4-pentadiene (31): 1H NMR (400 MHz, CDCl3) cis isomer δ 7.36-7.19 (m, 5H), 6.52 (d, J ) 11.57 Hz, 1H), 5.965.86 (m, 1H), 5.71 (dt, J ) 11.54, 7.57 Hz, 1H), 5.11 (d, J ) 17.13 Hz, 1H), 5.07 (d, J ) 10.12 Hz, 1H), 3.06 (t, J ) 9.02 Hz, 2H), trans isomer δ 7.36-7.19 (m, 5H), 6.41 (d, J ) 15.90 Hz, 1H), 6.23 (dt, J ) 15.77, 6.66 Hz, 1H), 5.96-5.86 (m, 1H), 5.11 (d, J ) 17.13 Hz, 1H), 5.07 (d, J ) 10.12 Hz, 1H), 2.96 (t, J ) 7.04 Hz, 2H); 13C NMR (100 MHz, CDCl3) cis isomer δ 137.29, 136.66, 130.05, 129.47, 128.63, 128.17, 126.71, 115.28, 32.70, trans isomer δ 137.62, 136.47, 130.85, 128.49, 128.18, 127.02, 126.04, 115.67, 37.00; IR (film) 3053, 2986, 2305, 1422, 1269 cm-1; HRMS (EI) calcd for C11H12 M+ 144.0939, found 144.0933 (cis isomer), 144.0935 (trans isomer). 2-Allyl-1-phenyl-1,4-pentadiene (32): 1H NMR (400 MHz, CDCl3) δ 7.33-7.18 (m, 5H), 6.41 (s, 1H), 5.93-5.83 (m, 2H), 5.12 (d, J ) 8.32 Hz, 2H), 5.07 (d, J ) 15.97 Hz, 2H), 2.99 (d, J ) 5.94 Hz, 2H), 2.92 (d, J ) 6.76 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 134.97, 132.73, 131.16, 128.47, 127.71, 126.23, 121.03, 115.97, 40.91, 34.93; IR (film) 3054, 2987, 1530, 1423, 1267 cm-1; HRMS (EI) calcd for C14H16 M+ 184.1252, found 184.1250. 2-(2′-Cyclohexenyl)-2-cyclohexen-1-one (33): 1H NMR (400 MHz, CDCl3) δ 6.71 (t, J ) 4.22 Hz, 1H), 5.87-5.82 (m, 1H), 5.45-5.41 (m, 1H), 3.44 (s, 1H), 2.44 (t, J ) 6.54 Hz, 2H), 2.38 (q, J ) 10.32 Hz, 2H), 2.01-1.96 (m, 4H), 1.88-1.81 (m, 1H), 1.59-1.50 (m, 2H), 1.33-1.26 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 198.81, 145.56, 143.04, 129.17, 128.85, 38.80, 33.36, 28.90, 26.12, 25.12, 23.09, 20.07; IR (film) 3053, 2986, 2305, 1733, 1422, 1269 cm-1; HRMS (EI) calcd for C12H16O M+ 176.1201, found 176. 1199. 3-Allyl-2-cyclohexen-1-one (34): 1H NMR (400 MHz, CDCl3) δ 5.77 (s, 1H), 5.80 (ddt, J ) 17.01, 10.25, 6.87 Hz, 1H), 5.16 (d, J ) 10.25 Hz, 1H), 5.14 (d, J ) 17.01 Hz, 1H), 2.95 (d, J ) 6.87 Hz, 2H), 2.39 (t, J ) 7.59 Hz, 2H), 2.30 (t, J ) 6.00 Hz, 2H), 2.00 (quint, J ) 6.25 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 199.91, 164.21, 133.26, 126.28, 118.31, 42.22, 37.32, 29.48, 22.63; IR (film) 3055, 2985, 2305, 1733, 1422, 1265 cm-1; HRMS (EI) calcd for C9H12O M+ 136.0888, found 136.0885. 3-(2′-Cyclohexenyl)-2-cyclohexen-1-one (35): 1H NMR (400 MHz, CDCl3) δ 5.88 (s, 1H), 5.87-5.85 (m, 1H), 5.52 (dd, J ) 10.07, 2.28 Hz, 1H), 2.90-2.94 (m, 1H), 2.41-2.34 (m, 4H), 2.26-2.19 (m, 2H), 2.03-1.96 (m, 4H), 1.91-1.84 (m, 1H), 1.741.67 (m, 2H), 1.57-1.50 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 200.24, 169.57, 132.34, 129.77, 122.35, 43.28, 37.60, 37.54, 34.67, 31.60, 28.35, 20.64; IR (film) 3055, 2986, 1733, 1422, 1269 cm-1; HRMS (EI) calcd for C12H16O M+ 176.1201, found 176.1199. 5-Methyl-1-phenyl-1-hex-4-en-1-yne (36): 1H NMR (400 MHz, CDCl3) δ 7.53 (d, J ) 7.87 Hz, 2H), 7.40-7.31 (m, 3H), 5.40 (t, J ) 6.82 Hz, 1H), 3.76 (d, J ) 6.82 Hz, 1H), 1.80 (s, 3H), 1.76 (s, 3H); 13C NMR (100 MHz, CDCl3) δ 134.70, 132.52, 129.21, 128.45, 121.80, 117.90, 81.55, 73.90, 42.50, 39.65; IR (film) 3540, 2986, 1422, 1269 cm-1; HRMS (EI) calcd for C13H14 M+ 170.1096, found 170.1091.

Acknowledgment. This work was supported by the Korea Research Foundation (KRF-99-005-D00048). We thank Whasook Choi for the preliminary experiments. The gas chromatograms were provided by the GC facility, supported by the Research Center for Advanced Mineral Aggregate Composite Products. Supporting Information Available: 1H and 13C NMR spectra. This material is available free of charge via the Internet at http://pubs.acs.org. JO026121U